Miniskirt tape head having quasi-statically tilted transducer arrays

ABSTRACT

In one general embodiment, an apparatus includes a magnetic head. The magnetic head has a first portion and a second portion, the first portion and the second portion together providing a tape bearing surface. The first portion has two pieces flanking the second portion in an intended direction of tape travel thereacross. The second portion has at least one array of transducers. A longitudinal axis of each of the at least one array is defined between opposite ends thereof. The longitudinal axis of each of the at least one array of transducers is oriented at an angle relative to the line oriented orthogonally to the intended direction of tape travel thereacross, the angle being between 0.2° and about 10°.

BACKGROUND

The present invention relates to data storage systems, and moreparticularly, this invention relates to a magnetic head and systemimplementing the same, where the head includes a miniskirt design incombination with offset transducer arrays that are selectively tiltablerelative to a magnetic medium.

In magnetic storage systems, data is read from and written onto magneticrecording media utilizing magnetic transducers. Data is written on themagnetic recording media by moving a magnetic recording transducer to aposition over the media where the data is to be stored. The magneticrecording transducer then generates a magnetic field, which encodes thedata into the magnetic media. Data is read from the media by similarlypositioning the magnetic read transducer and then sensing the magneticfield of the magnetic media. Read and write operations may beindependently synchronized with the movement of the media to ensure thatthe data can be read from and written to the desired location on themedia.

An important and continuing goal in the data storage industry is that ofincreasing the density of data stored on a medium. For tape storagesystems, that goal has led to increasing the track and linear bitdensity on recording tape, and decreasing the thickness of the magnetictape medium. However, the development of small footprint, higherperformance tape drive systems has created various problems in thedesign of a tape head assembly for use in such systems.

In a tape drive system, magnetic tape is moved over the surface of thetape head at high speed. Usually the tape head is designed to minimizethe spacing between the head and the tape. The spacing between themagnetic head and the magnetic tape is crucial and so goals in thesesystems are to have the recording gaps of the transducers, which are thesource of the magnetic recording flux in near contact with the tape toeffect writing sharp transitions, and to have the read elements in nearcontact with the tape to provide effective coupling of the magneticfield from the tape to the read elements.

The quantity of data stored on a magnetic tape may be increased byincreasing the number of data tracks across the tape. More tracks aremade possible by reducing feature sizes of the readers and writers, suchas by using thin-film fabrication techniques and MR sensors. However,for various reasons, the feature sizes of readers and writers cannot bearbitrarily reduced, and so factors such as lateral tape motiontransients and tape lateral expansion and contraction (e.g., orthogonalto the direction of tape travel) must be balanced with reader/writersizes that provide acceptable written tracks and readback signals. Oneissue limiting areal density is misregistration caused by tape lateralexpansion and contraction. Tape width can vary by up to about 0.1% dueto expansion and contraction caused by changes in humidity, tapetension, temperature, aging etc. This is often referred to as tapedimensional instability (TDI).

If the tape is written in one environment and then read back in another,the TDI may prevent the spacing of the tracks on the tape from preciselymatching the spacing of the reading elements during readback. In currentproducts, the change in track spacing due to TDI is small compared tothe size of the written tracks and is part of the tracking budget thatis considered when designing a product. As the tape capacity increasesover time, tracks are becoming smaller and TDI is becoming anincreasingly larger portion of the tracking budget and this is alimiting factor for growing areal density.

SUMMARY

An apparatus according to one embodiment includes a magnetic head. Themagnetic head has a first portion and a second portion, the firstportion and the second portion together providing a tape bearingsurface. The first portion has two pieces flanking the second portion inan intended direction of tape travel thereacross. The second portion hasat least one array of transducers. A longitudinal axis of each of the atleast one array is defined between opposite ends thereof. Thelongitudinal axis of each of the at least one array of transducers isoriented at an angle relative to the line oriented orthogonally to theintended direction of tape travel thereacross, the angle being between0.2° and about 10°.

Any of these embodiments may be implemented in a magnetic data storagesystem such as a tape drive system, which may include a magnetic head, adrive mechanism for passing a magnetic medium (e.g., recording tape)over the magnetic head, and a controller electrically coupled to themagnetic head.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a simplified tape drive systemaccording to one embodiment.

FIG. 1B is a schematic diagram of a tape cartridge according to oneembodiment.

FIG. 2 illustrates a side view of a flat-lapped, bi-directional,two-module magnetic tape head according to one embodiment.

FIG. 2A is a tape bearing surface view taken from Line 2A of FIG. 2.

FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.

FIG. 2C is a detailed view of a partial tape bearing surface of a pairof modules.

FIG. 3 is a partial tape bearing surface view of a magnetic head havinga write-read-write configuration.

FIG. 4 is a partial tape bearing surface view of a magnetic head havinga read-write-read configuration.

FIG. 5 is a side view of a magnetic tape head with three modulesaccording to one embodiment where the modules all generally lie alongabout parallel planes.

FIG. 6 is a side view of a magnetic tape head with three modules in atangent (angled) configuration.

FIG. 7 is a side view of a magnetic tape head with three modules in anoverwrap configuration.

FIGS. 8A-8C are partial top-down views of one module of a magnetic tapehead according to one embodiment.

FIGS. 9A-9C are partial top-down views of one module of a magnetic tapehead according to one embodiment.

FIG. 10 is a partial top-down view of a module according to oneembodiment.

FIGS. 11A-11B are partial top-down views of an apparatus with twomodules according to one embodiment.

FIG. 11C is a diagram of the system of FIGS. 11A-11B.

FIG. 11D is a partial top-down view of an apparatus with two modulesaccording to one embodiment.

FIG. 12 is a partial top-down view of an apparatus with two modulesaccording to one embodiment.

FIG. 13A is a partial top-down view of an apparatus having two portionsaccording to one embodiment.

FIG. 13B is a partial cross-sectional view of the embodiment shown inFIG. 13A taken along line 13B-13B.

FIG. 14 is a partial top-down view of an apparatus having two portionsaccording to one embodiment.

FIG. 15 is a partial top-down view of an apparatus having two portionsaccording to one embodiment.

FIG. 16 is a partial top-down view of an apparatus having two portionsaccording to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments ofmagnetic storage systems, in which a magnetic head incorporates aminiskirt design in combination with tilted arrays, as well as operationand/or component parts thereof. In various embodiments, the miniskirtdesign may allow for relative motion between portions of the tapesupporting surface, thereby increasing the data read and/or writeperformance of some of the embodiments presented herein, as will bediscussed in further detail below.

In one general embodiment, an apparatus includes a magnetic head. Themagnetic head has a first portion and a second portion, the firstportion and the second portion together providing a tape bearingsurface. The first portion has an opening at least partially encirclingthe second portion. The second portion has at least one array oftransducers. A longitudinal axis of each of the at least one array isdefined between opposite ends thereof. The longitudinal axis of each ofthe at least one array of transducers is oriented at an angle relativeto a line oriented orthogonally to the intended direction of tape travelthereacross, the angle being between 0.2° and about 10°.

In another general embodiment, an apparatus includes a magnetic head.The magnetic head has a first portion and a second portion, the firstportion and the second portion together providing a tape bearingsurface. The tape bearing surface has a generally arcuate crosssectional profile. The first portion has an opening at least partiallyencircling the second portion. The second portion has at least one arrayof transducers. A longitudinal axis of each of the at least one array isdefined between opposite ends thereof. The longitudinal axis of each ofthe at least one array of transducers is oriented at an angle relativeto a line oriented orthogonal to the intended direction of tape travelthereacross, the angle being between 0.2° and about 10°. The apparatusalso includes a mechanism for orienting the second portion to control atransducer pitch presented to a tape, a drive mechanism for passing amagnetic medium over the magnetic head, and a controller electricallycoupled to the magnetic head.

FIG. 1A illustrates a simplified tape drive 100 of a tape-based datastorage system, which may be employed in the context of the presentinvention. While one specific implementation of a tape drive is shown inFIG. 1A, it should be noted that the embodiments described herein may beimplemented in the context of any type of tape drive system.

As shown, a tape supply cartridge 120 and a take-up reel 121 areprovided to support a tape 122. One or more of the reels may form partof a removable cartridge and are not necessarily part of the system 100.The tape drive, such as that illustrated in FIG. 1A, may further includedrive motor(s) to drive the tape supply cartridge 120 and the take-upreel 121 to move the tape 122 over a tape head 126 of any type. Suchhead may include an array of readers, writers, or both.

Guides 125 guide the tape 122 across the tape head 126. Such tape head126 is in turn coupled to a controller 128 via a cable 130. Thecontroller 128, may be or include a processor and/or any logic forcontrolling any subsystem of the drive 100. For example, the controller128 typically controls head functions such as servo following, datawriting, data reading, etc. The controller 128 may operate under logicknown in the art, as well as any logic disclosed herein. The controller128 may be coupled to a memory 136 of any known type, which may storeinstructions executable by the controller 128. Moreover, the controller128 may be configured and/or programmable to perform or control some orall of the methodology presented herein. Thus, the controller may beconsidered configured to perform various operations by way of logicprogrammed into a chip; software, firmware, or other instructions beingavailable to a processor; etc. and combinations thereof.

The cable 130 may include read/write circuits to transmit data to thehead 126 to be recorded on the tape 122 and to receive data read by thehead 126 from the tape 122. An actuator 132 controls position of thehead 126 relative to the tape 122.

An interface 134 may also be provided for communication between the tapedrive 100 and a host (integral or external) to send and receive the dataand for controlling the operation of the tape drive 100 andcommunicating the status of the tape drive 100 to the host, all as willbe understood by those of skill in the art.

FIG. 1B illustrates an exemplary tape cartridge 150 according to oneembodiment. Such tape cartridge 150 may be used with a system such asthat shown in FIG. 1A. As shown, the tape cartridge 150 includes ahousing 152, a tape 122 in the housing 152, and a nonvolatile memory 156coupled to the housing 152. In some embodiments, the nonvolatile memory156 may be embedded inside the housing 152, as shown in FIG. 1B. In moreembodiments, the nonvolatile memory 156 may be attached to the inside oroutside of the housing 152 without modification of the housing 152. Forexample, the nonvolatile memory may be embedded in a self-adhesive label154. In one preferred embodiment, the nonvolatile memory 156 may be aFlash memory device, ROM device, etc., embedded into or coupled to theinside or outside of the tape cartridge 150. The nonvolatile memory isaccessible by the tape drive and the tape operating software (the driversoftware), and/or other device.

By way of example, FIG. 2 illustrates a side view of a flat-lapped,bi-directional, two-module magnetic tape head 200 which may beimplemented in the context of the present invention. As shown, the headincludes a pair of bases 202, each equipped with a module 204, and fixedat a small angle α with respect to each other. The bases may be“U-beams” that are adhesively coupled together. Each module 204 includesa substrate 204A and a closure 204B with a thin film portion, commonlyreferred to as a “gap” in which the readers and/or writers 206 areformed. In use, a tape 208 is moved over the modules 204 along a media(tape) bearing surface 209 in the manner shown for reading and writingdata on the tape 208 using the readers and writers. The wrap angle θ ofthe tape 208 at edges going onto and exiting the flat media supportsurfaces 209 are usually between about 0.1 degree and about 3 degrees.

The substrates 204A are typically constructed of a wear resistantmaterial, such as a ceramic. The closures 204B made of the same orsimilar ceramic as the substrates 204A.

The readers and writers may be arranged in a piggyback or mergedconfiguration. An illustrative piggybacked configuration comprises a(magnetically inductive) writer transducer on top of (or below) a(magnetically shielded) reader transducer (e.g., a magnetoresistivereader, etc.), wherein the poles of the writer and the shields of thereader are generally separated. An illustrative merged configurationcomprises one reader shield in the same physical layer as one writerpole (hence, “merged”). The readers and writers may also be arranged inan interleaved configuration. Alternatively, each array of channels maybe readers or writers only. Any of these arrays may contain one or moreservo track readers for reading servo data on the medium.

FIG. 2A illustrates the tape bearing surface 209 of one of the modules204 taken from Line 2A of FIG. 2. A representative tape 208 is shown indashed lines. The module 204 is preferably long enough to be able tosupport the tape as the head steps between data bands.

In this example, the tape 208 includes 4 to 22 data bands, e.g., with 8data bands and 9 servo tracks 210, as shown in FIG. 2A on a one-halfinch wide tape 208. The data bands are defined between servo tracks 210.Each data band may include a number of data tracks, for example 1024data tracks (not shown). During read/write operations, the readersand/or writers 206 are positioned to specific track positions within oneof the data bands. Outer readers, sometimes called servo readers, readthe servo tracks 210. The servo signals are in turn used to keep thereaders and/or writers 206 aligned with a particular set of tracksduring the read/write operations.

FIG. 2B depicts a plurality of readers and/or writers 206 formed in agap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the arrayof readers and writers 206 includes, for example, 16 writers 214, 16readers 216 and two servo readers 212, though the number of elements mayvary. Illustrative embodiments include 8, 16, 32, 40, and 64 activereaders and/or writers 206 per array, and alternatively interleaveddesigns having odd numbers of reader or writers such as 17, 25, 33, etc.An illustrative embodiment includes 32 readers per array and/or 32writers per array, where the actual number of transducer elements couldbe greater, e.g., 33, 34, etc. This allows the tape to travel moreslowly, thereby reducing speed-induced tracking and mechanicaldifficulties and/or execute fewer “wraps” to fill or read the tape.While the readers and writers may be arranged in a piggybackconfiguration as shown in FIG. 2B, the readers 216 and writers 214 mayalso be arranged in an interleaved configuration. Alternatively, eacharray of readers and/or writers 206 may be readers or writers only, andthe arrays may contain one or more servo readers 212. As noted byconsidering FIGS. 2 and 2A-B together, each module 204 may include acomplementary set of readers and/or writers 206 for such things asbi-directional reading and writing, read-while-write capability,backward compatibility, etc.

FIG. 2C shows a partial tape bearing surface view of complimentarymodules of a magnetic tape head 200 according to one embodiment. In thisembodiment, each module has a plurality of read/write (R/W) pairs in apiggyback configuration formed on a common substrate 204A and anoptional electrically insulative layer 236. The writers, exemplified bythe write transducer 214 and the readers, exemplified by the readtransducer 216, are aligned parallel to an intended direction of travelof a tape medium thereacross to form an R/W pair, exemplified by the R/Wpair 222. Note that the intended direction of tape travel is sometimesreferred to herein as the direction of tape travel, and such terms maybe used interchangeable. Such direction of tape travel may be inferredfrom the design of the system, e.g., by examining the guides; observingthe actual direction of tape travel relative to the reference point;etc. Moreover, in a system operable for bi-direction reading and/orwriting, the direction of tape travel in both directions is typicallyparallel and thus both directions may be considered equivalent to eachother.

Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. TheR/W pairs 222 as shown are linearly aligned in a direction generallyorthogonal to a direction of tape travel thereacross. However, the pairsmay also be aligned diagonally, etc. Servo readers 212 are positioned onthe outside of the array of R/W pairs, the function of which is wellknown.

Generally, the magnetic tape medium moves in either a forward or reversedirection as indicated by arrow 220. The magnetic tape medium and headassembly 200 operate in a transducing relationship in the mannerwell-known in the art. The piggybacked MR head assembly 200 includes twothin-film modules 224 and 226 of generally identical construction.

Modules 224 and 226 are joined together with a space present betweenclosures 204B thereof (partially shown) to form a single physical unitto provide read-while-write capability by activating the writer of theleading module and reader of the trailing module aligned with the writerof the leading module parallel to the direction of tape travel relativethereto. When a module 224, 226 of a piggyback head 200 is constructed,layers are formed in the gap 218 created above an electricallyconductive substrate 204A (partially shown), e.g., of AITiC, ingenerally the following order for the R/W pairs 222: an insulating layer236, a first shield 232 typically of an iron alloy such as NiFe (−), CZTor Al—Fe—Si (Sendust), a sensor 234 for sensing a data track on amagnetic medium, a second shield 238 typically of a nickel-iron alloy(e.g., ˜80/20 at % NiFe, also known as permalloy), first and secondwriter pole tips 228, 230, and a coil (not shown). The sensor may be ofany known type, including those based on MR, GMR, AMR, tunnelingmagnetoresistance (TMR), etc.

The first and second writer poles 228, 230 may be fabricated from highmagnetic moment materials such as ˜45/55 NiFe. Note that these materialsare provided by way of example only, and other materials may be used.Additional layers such as insulation between the shields and/or poletips and an insulation layer surrounding the sensor may be present.Illustrative materials for the insulation include alumina and otheroxides, insulative polymers, etc.

The configuration of the tape head 126 according to one embodimentincludes multiple modules, preferably three or more. In awrite-read-write (W-R-W) head, outer modules for writing flank one ormore inner modules for reading. Referring to FIG. 3, depicting a W-R-Wconfiguration, the outer modules 252, 256 each include one or morearrays of writers 260. The inner module 254 of FIG. 3 includes one ormore arrays of readers 258 in a similar configuration. Variations of amulti-module head include a R-W-R head (FIG. 4), a R-R-W head, a W-W-Rhead, etc. In yet other variations, one or more of the modules may haveread/write pairs of transducers. Moreover, more than three modules maybe present. In further embodiments, two outer modules may flank two ormore inner modules, e.g., in a W-R-R-W, a R-W-W-R arrangement, etc. Forsimplicity, a W-R-W head is used primarily herein to exemplifyembodiments of the present invention. One skilled in the art apprisedwith the teachings herein will appreciate how permutations of thepresent invention would apply to configurations other than a W-R-Wconfiguration.

FIG. 5 illustrates a magnetic head 126 according to one embodiment ofthe present invention that includes first, second and third modules 302,304, 306 each having a tape bearing surface 308, 310, 312 respectively,which may be flat, contoured, etc. Note that while the term “tapebearing surface” appears to imply that the surface facing the tape 315is in physical contact with the tape bearing surface, this is notnecessarily the case. Rather, only a portion of the tape may be incontact with the tape bearing surface, constantly or intermittently,with other portions of the tape riding (or “flying”) above the tapebearing surface on a layer of air, sometimes referred to as an “airbearing”. The first module 302 will be referred to as the “leading”module as it is the first module encountered by the tape in a threemodule design for tape moving in the indicated direction. The thirdmodule 306 will be referred to as the “trailing” module. The trailingmodule follows the middle module and is the last module seen by the tapein a three module design. The leading and trailing modules 302, 306 arereferred to collectively as outer modules. Also note that the outermodules 302, 306 will alternate as leading modules, depending on thedirection of travel of the tape 315.

In one embodiment, the tape bearing surfaces 308, 310, 312 of the first,second and third modules 302, 304, 306 lie on about parallel planes(which is meant to include parallel and nearly parallel planes, e.g.,between parallel and tangential as in FIG. 6), and the tape bearingsurface 310 of the second module 304 is above the tape bearing surfaces308, 312 of the first and third modules 302, 306. As described below,this has the effect of creating the desired wrap angle α₂ of the taperelative to the tape bearing surface 310 of the second module 304.

Where the tape bearing surfaces 308, 310, 312 lie along parallel ornearly parallel yet offset planes, intuitively, the tape should peel offof the tape bearing surface 308 of the leading module 302. However, thevacuum created by the skiving edge 318 of the leading module 302 hasbeen found by experimentation to be sufficient to keep the tape adheredto the tape bearing surface 308 of the leading module 302. The trailingedge 320 of the leading module 302 (the end from which the tape leavesthe leading module 302) is the approximate reference point which definesthe wrap angle α₂ over the tape bearing surface 310 of the second module304. The tape stays in close proximity to the tape bearing surface untilclose to the trailing edge 320 of the leading module 302. Accordingly,read and/or write elements 322 may be located near the trailing edges ofthe outer modules 302, 306. These embodiments are particularly adaptedfor write-read-write applications.

A benefit of this and other embodiments described herein is that,because the outer modules 302, 306 are fixed at a determined offset fromthe second module 304, the inner wrap angle α₂ is fixed when the modules302, 304, 306 are coupled together or are otherwise fixed into a head.The inner wrap angle α₂ is approximately tan⁻¹(δ/W) where δ is theheight difference between the planes of the tape bearing surfaces 308,310 and W is the width between the opposing ends of the tape bearingsurfaces 308, 310. An illustrative inner wrap angle α₂ is in a range ofabout 0.3° to about 1.1°, though can be any angle required by thedesign.

Beneficially, the inner wrap angle α₂ on the side of the module 304receiving the tape (leading edge) will be larger than the inner wrapangle α₃ on the trailing edge, as the tape 315 rides above the trailingmodule 306. This difference is generally beneficial as a smaller astends to oppose what has heretofore been a steeper exiting effectivewrap angle.

Note that the tape bearing surfaces 308, 312 of the outer modules 302,306 are positioned to achieve a negative wrap angle at the trailing edge320 of the leading module 302. This is generally beneficial in helpingto reduce friction due to contact with the trailing edge 320, providedthat proper consideration is given to the location of the crowbar regionthat forms in the tape where it peels off the head. This negative wrapangle also reduces flutter and scrubbing damage to the elements on theleading module 302. Further, at the trailing module 306, the tape 315flies over the tape bearing surface 312 so there is virtually no wear onthe elements when tape is moving in this direction. Particularly, thetape 315 entrains air and so will not significantly ride on the tapebearing surface 312 of the third module 306 (some contact may occur).This is permissible, because the leading module 302 is writing while thetrailing module 306 is idle.

Writing and reading functions are performed by different modules at anygiven time. In one embodiment, the second module 304 includes aplurality of data and optional servo readers 331 and no writers. Thefirst and third modules 302, 306 include a plurality of writers 322 andno data readers, with the exception that the outer modules 302, 306 mayinclude optional servo readers. The servo readers may be used toposition the head during reading and/or writing operations. The servoreader(s) on each module are typically located towards the end of thearray of readers or writers.

By having only readers or side by side writers and servo readers in thegap between the substrate and closure, the gap length can besubstantially reduced. Typical heads have piggybacked readers andwriters, where the writer is formed above each reader. A typical gap is20-35 microns. However, irregularities on the tape may tend to droopinto the gap and create gap erosion. Thus, the smaller the gap is thebetter. The smaller gap enabled herein exhibits fewer wear relatedproblems.

In some embodiments, the second module 304 has a closure, while thefirst and third modules 302, 306 do not have a closure. Where there isno closure, preferably a hard coating is added to the module. Onepreferred coating is diamond-like carbon (DLC).

In the embodiment shown in FIG. 5, the first, second, and third modules302, 304, 306 each have a closure 332, 334, 336, which extends the tapebearing surface of the associated module, thereby effectivelypositioning the read/write elements away from the edge of the tapebearing surface. The closure 332 on the second module 304 can be aceramic closure of a type typically found on tape heads. The closures334, 336 of the first and third modules 302, 306, however, may beshorter than the closure 332 of the second module 304 as measuredparallel to a direction of tape travel over the respective module. Thisenables positioning the modules closer together. One way to produceshorter closures 334, 336 is to lap the standard ceramic closures of thesecond module 304 an additional amount. Another way is to plate ordeposit thin film closures above the elements during thin filmprocessing. For example, a thin film closure of a hard material such asSendust or nickel-iron alloy (e.g., 45/55) can be formed on the module.

With reduced-thickness ceramic or thin film closures 334, 336 or noclosures on the outer modules 302, 306, the write-to-read gap spacingcan be reduced to less than about 1 mm, e.g., about 0.75 mm, or 50% lessthan commonly-used LTO tape head spacing. The open space between themodules 302, 304, 306 can still be set to approximately 0.5 to 0.6 mm,which in some embodiments is ideal for stabilizing tape motion over thesecond module 304.

Depending on tape tension and stiffness, it may be desirable to anglethe tape bearing surfaces of the outer modules relative to the tapebearing surface of the second module. FIG. 6 illustrates an embodimentwhere the modules 302, 304, 306 are in a tangent or nearly tangent(angled) configuration. Particularly, the tape bearing surfaces of theouter modules 302, 306 are about parallel to the tape at the desiredwrap angle α₂ of the second module 304. In other words, the planes ofthe tape bearing surfaces 308, 312 of the outer modules 302, 306 areoriented at about the desired wrap angle α₂ of the tape 315 relative tothe second module 304. The tape will also pop off of the trailing module306 in this embodiment, thereby reducing wear on the elements in thetrailing module 306. These embodiments are particularly useful forwrite-read-write applications. Additional aspects of these embodimentsare similar to those given above.

Typically, the tape wrap angles may be set about midway between theembodiments shown in FIGS. 5 and 6.

FIG. 7 illustrates an embodiment where the modules 302, 304, 306 are inan overwrap configuration. Particularly, the tape bearing surfaces 308,312 of the outer modules 302, 306 are angled slightly more than the tape315 when set at the desired wrap angle α₂ relative to the second module304. In this embodiment, the tape does not pop off of the trailingmodule, allowing it to be used for writing or reading. Accordingly, theleading and middle modules can both perform reading and/or writingfunctions while the trailing module can read any just-written data.Thus, these embodiments are preferred for write-read-write,read-write-read, and write-write-read applications. In the latterembodiments, closures should be wider than the tape canopies forensuring read capability. The wider closures may require a widergap-to-gap separation. Therefore a preferred embodiment has awrite-read-write configuration, which may use shortened closures thatthus allow closer gap-to-gap separation.

Additional aspects of the embodiments shown in FIGS. 6 and 7 are similarto those given above.

A 32 channel version of a multi-module head 126 may use cables 350having leads on the same or smaller pitch as current 16 channelpiggyback LTO modules, or alternatively the connections on the modulemay be organ-keyboarded for a 50% reduction in cable span. Over-under,writing pair unshielded cables may be used for the writers, which mayhave integrated servo readers.

The outer wrap angles α₁ may be set in the drive, such as by guides ofany type known in the art, such as adjustable rollers, slides, etc. oralternatively by outriggers, which are integral to the head. Forexample, rollers having an offset axis may be used to set the wrapangles. The offset axis creates an orbital arc of rotation, allowingprecise alignment of the wrap angle α₁.

To assemble any of the embodiments described above, conventional u-beamassembly can be used. Accordingly, the mass of the resultant head may bemaintained or even reduced relative to heads of previous generations. Inother embodiments, the modules may be constructed as a unitary body.Those skilled in the art, armed with the present teachings, willappreciate that other known methods of manufacturing such heads may beadapted for use in constructing such heads.

As noted above, tape lateral expansion and contraction present manychallenges to increasing data track density on conventional products.Conventional products have attempted to compensate for tape lateralexpansion and contraction by controlling tape width by tension andimproving the characteristics of the media itself. However, thesemethods fail to fully cancel the tape lateral expansion and contraction,and actually lead to other problems, including tape stretch and mediacost increases, respectively.

FIGS. 8A-8C are intended to depict the effect of tape lateral expansionand contraction on transducer arrays position relative thereto, and arein no way intended to limit the invention. FIG. 8A depicts a module 800relative to the tape 802, where the tape has a nominal width. As shown,the transducers 804 are favorably aligned with the data tracks 806 onthe tape 802. However, FIG. 8B illustrates the effect of tape lateralcontraction. As shown, contraction of the tape causes the data tracks tocontract as well, and the outermost transducers 808 are positioned alongthe outer edges of the outer data tracks as a result. Moreover, FIG. 8Cdepicts the effect of tape lateral expansion. Here expansion of the tapecauses the data tracks to move farther apart, and the outermosttransducers 808 are positioned along the inner edges of the outer datatracks as a result. If the tape lateral contraction is greater than thatshown in FIG. 8B, or the tape lateral expansion is greater than thatshown in FIG. 8C, the outermost transducers 808 will cross onto adjacenttracks, thereby causing the data stored on adjacent tracks to beoverwritten during a writing operation and/or resulting in readback ofthe wrong track during a readback operation. Moreover, running effects,such as tape skew and lateral shifting may exacerbate such problems,particularly for tape having shingled data tracks.

Thus, it would be desirable to develop a tape drive system able to readand/or write tracks onto the tape in the proper position, regardless ofthe extent of tape lateral expansion and/or contraction at any giventime. Various embodiments described and/or suggested herein overcome theforegoing challenges of conventional products, by orienting at least twomodules of a tape drive system, such as by rotating, pivoting and/ortilting, thereby selectively altering the pitch of the transducers intheir arrays, as will soon become apparent.

By selectively orienting a module, the pitch of the transducers on themodule is thereby altered, preferably aligning the transducers with thetracks on a tape for a given tape lateral expansion and/or contraction.Tape contraction (shrinkage) can be dealt with by orienting a nominallynon-offset head, but tape expansion (dilation) cannot. Thus, toaccommodate both shrinkage and dilation about a “nominal,” the head mustbe statically positioned at a nominal angle of at least approximately0.2° as will be explained below. Thereafter, smaller angular adjustments(e.g., about 1° or lower, but could be more) may be made to thealready-oriented module in order to compensate for any variation of thetape lateral expansion and/or contraction, thereby keeping thetransducers aligned with tracks on the tape.

FIGS. 9A-9C illustrate representational views of the effects oforienting a module having transducer arrays. It should be noted that theangles of orientation illustrated in FIGS. 9A-9C are an exaggeration(e.g., larger than would typically be observed), and are in no wayintended to limit the invention.

Referring to FIG. 9A, the module 900 is shown relative to the tape 902,where the tape has a nominal width. As illustrated, the module 900 isoriented at an angle θ_(nom) such that the transducers 904 are favorablyaligned with the data tracks 906 on the tape 902. However, when the tape902 experiences tape lateral contraction and/or expansion, the datatracks 906 on the tape contract and/or expand as well. As a result, thetransducers on the module are no longer favorably aligned with the datatracks 906 on the tape 902.

In FIG. 9B, the tape 902 has experienced tape lateral contraction.Therefore, in a manner exemplified by FIG. 8B, the transducers 904 onthe module 900 of FIG. 9B would no longer be favorably aligned with thedata tracks 906 on the tape 902 if no adjustment were made. However, asalluded to above, smaller angular adjustments may be made to thealready-oriented module 900 in order to compensate for tape lateralcontraction. Therefore, referring again to FIG. 9B, the angle oforientation >θ_(nom) of the module 900 is further positioned at an anglegreater than θ_(nom). By increasing the angle >θ_(nom) the effectivewidth w₂ of the array of transducers decreases from the effective widthw₁ illustrated in FIG. 9A. This also translates to a reduction in theeffective pitch between the transducers, thereby realigning thetransducers along the contracted data tracks 906 on the tape 902 asshown in FIG. 9B.

On the other hand, when the tape experiences tape lateral expansion, thedata tracks on the tape expand as well. As a result, the transducers onthe module would no longer be favorably aligned with the data tracks onthe tape if no adjustments were made. With reference to FIG. 9C, thetape 902 has experienced tape lateral expansion. As a result, furtherangular adjustments may be made to the angle of orientation of themodule in order to compensate for the tape lateral expansion. Therefore,referring again to FIG. 9C, the angle of orientation <θ_(nom) of themodule 900 is reduced to an angle less than θ_(nom). By decreasing theangle of orientation <θ_(nom) the effective width w₃ of the array oftransducers 904 increases from the effective width w₁ illustrated inFIG. 9A. Moreover, reducing the effective width of the array oftransducers 904 also causes the effective pitch between the transducersto be reduced, thereby realigning the transducers along the data tracks906 on the tape 902.

In some preferred embodiments, magnetic tape systems include two or morearrays of transducers, on one or more modules, where each array hasmultiple transducers typically arranged in a row. Depending on thedesired embodiment, the multiple rows of transducers may allow thesystem to read verify during the write process, but is not limitedthereto. As mentioned above, the foregoing conventional challenges maybe overcome, e.g., by rotating a given module about an axis orthogonalto the plane in which its array resides (e.g., parallel to the plane ofthe tape bearing surface), thereby selectively altering the pitch of thetransducers in the array as presented to tape. Moreover, similar effectsmay be achieved by changing the orientation of the array of transducerswithin the module itself according to another embodiment.

By providing a system that compensates for tape lateral expansion and/orcontraction, various embodiments enable use of wider readers, resultingin a better signal to noise ratio (SNR), and/or smaller data tracks,thereby enabling in a higher capacity per unit area of the media.

Furthermore, a miniskirt design which may, for example, haveindependently positionable portions of a magnetic head, may beincorporated with any of the embodiments described herein. The miniskirtmay provide a low running friction tape support surface that reducesfriction compared to a conventional head. In addition, the miniskirtenables the use of smaller, lower mass modules (relative to a modulethat spans the entire tape width), and this in turn may provide highertrack following performance.

The miniskirt design may preferably allow relative motion betweenportions of a magnetic head which together may provide a tape bearingsurface. As described above, this may desirably increase the data readand/or write performance of various embodiments presented herein byimproving compensation for tape skew; shifting (as detected usingposition error signal (PES) processing); TDI, e.g., lateral contractionand/or expansion, etc.; etc. Moreover, according to further embodiments,when paired with selectively tiltable data transducers as describedabove with reference to FIGS. 9A-9C, the miniskirt design may provideeven greater improvements to data read and/or write performance, as willbe explored in further detail below with reference to FIGS. 13A-15.

Furthermore, the miniskirt (referred to below as the “first portion”)may reduce running friction, especially in embodiments where theminiskirt has an arcuate cross sectional profile, thereby promotingentrainment of air between the running tape and miniskirt.

Moreover, the miniskirt may reduce static friction, also known asstiction, especially where the tape bearing surface of the miniskirt hasa surface roughness greater than 15 nm, e.g., 15-25 nm. The surface ofthe miniskirt may have a higher surface roughness than the tape bearingsurface of a module having a transducer array.

Looking now to FIG. 10, an apparatus 1000 for compensating for tapelateral expansion and/or contraction is depicted in accordance with oneembodiment. As an option, the present system 1000 may be implemented inconjunction with features from any other embodiment listed herein, suchas those described with reference to the other FIGS. Of course, however,system 1000 and others presented herein may be used in variousapplications and/or in permutations which may or may not be specificallydescribed in the illustrative embodiments listed herein. Further, thesystem 1000 presented herein may be used in any desired environment.

As illustrated in FIG. 10, an apparatus 1000 includes a magnetic head1002. Moreover, the magnetic head 1002 has a tape bearing surface 1004having a first edge 1006. According to one embodiment, the first edge1006 may preferably be oriented about orthogonal to an intendeddirection 1008 of tape travel thereacross, but is not limited theretodepending on the desired embodiment (discussed in further detail below).

With continued reference to FIG. 10, the system further includes acanted array 1010 of transducers 1012 in and/or adjacent the tapebearing surface 1004, the array 1010 of transducers 1012 having alongitudinal axis 1014 that is oriented at an angle φ, relative to thefirst edge 1006. According to various embodiments, the angle φ may bebetween greater than about 0.2° and about 10°, but could be higher orlower e.g., to compensate for tape lateral expansion, skew, PES, etc.,depending on the desired embodiment (discussed in further detail below).The angle 9 preferably keeps the transducers 1012 within theirrespective data tracks 906 on the tape 902, e.g., at least for a nominaltape width. Moreover, small angular adjustments may additionally be madeto the modules themselves to compensate for changing tape conditions aswill soon become apparent.

FIGS. 11A-11C depict an apparatus and system 1100 to compensate for tapelateral expansion and/or contraction, in accordance with an illustrativeembodiment having two modules. As an option, the present system 1100 maybe implemented in conjunction with features from any other embodimentlisted herein, such as those described with reference to the other FIGS.Of course, however, system 1100 and others presented herein may be usedin various applications and/or in permutations which may or may not bespecifically described in the illustrative embodiments listed herein.Further, the system 1100 presented herein may be used in any desiredenvironment.

Referring to the illustrative embodiment depicted in FIGS. 11A-11C, thesystem 1100 includes a magnetic head 1101 which has two modules 1124,1126. The magnetic head 1101 further includes a tape bearing surface1102 and a second tape bearing surface 1104 spaced therefrom. Asillustrated, each of the tape bearing surfaces 1102, 1104 have a firstedge 1128, and a second edge 1130 opposite the first edge 1128. Thetransducers 1110 are arranged along longitudinal axes 1112 and 1113,extending between opposite ends of the associated array, and that areoriented at an angle from the first edge 1128 of the respective module.This configuration enables recording at a quasi-statically anglerelative to the tape motion direction, and then making small correctionsto that angle to cancel misregistration due to tape lateral dimensionalchanges, but with minimal steering forces on the tape. Steering forcesmay result when the tape wraps around a canted edge, particularly in thepresence of friction, which can be high for smoother, modern highdensity tapes.

In a preferred embodiment, the first edge 1128 of the tape bearingsurfaces 1102, 1104 is a skiving edge. This “skiving” edge serves toprevent air from being drawn into the gap between the tape bearingsurface and the tape, so that atmospheric pressure pushes the tape intocontact with the transducers. Even a small amount of rounding or slopeat the first edge may generate an air bearing, separating the tape fromthe tape bearing surface, thereby reducing the achievable recordingdensity due to spacing loss. Moreover, in other embodiments, a skivingedge may reduce tape steering, skew, etc. when in use. In someembodiments, before the tape passes over a first edge of the tapebearing surface, the tape may pass over an additional separated portion,or “outrigger,” which favorably positions a tape to embodiment theskiving edge at a desirable wrap angle.

In a preferred embodiment, the first and second edges 1128, 1130 of themodules are of the same type (e.g., shape, texture, etc.) such that thetape tracks the same over the first edge of the tape bearing surface, asit does over the second edge of the tape bearing surface. This isparticularly favorable when tape is run over a head bidirectionally,e.g., the first edge of a tape bearing surface may be the leading ortrailing edge, depending on the desired direction of tape travel. Thisimproves read and/or write accuracy, reduces noise, increases recordingdensity, etc. However, in other embodiments the first and/or secondedges of one or more of the modules may have a different shape, texture,etc. than one or more of the other first and/or second edges, dependingon the desired embodiment.

With continued reference to FIGS. 11A-11C, the magnetic head 1101 hasarrays 1106, 1108 of transducers 1110 in and/or adjacent the tapebearing surfaces 1102, 1104, respectively. As illustrated, the arrays1106, 1108 of transducers are preferably longitudinally oriented at anangle 9 relative to the first edge 1128 of the tape bearing surfaces1102, 1104, respectively. As mentioned above, this angle 9 preferablyaligns the transducers within their respective data tracks 906 on thetape 902 e.g., when the modules are nominally oriented. According tovarious embodiments, the angle φ may be between greater than about 0.05°and about 10°, more preferably between greater than about 0.2° and about10°, and ideally between greater than about 0.25° and about 4.5°,relative to the first edge 1128 of the tape bearing surfaces 1102, 1104,respectively. However, this angle is effectively established after themodule is formed by any one or more of the methods described and/orsuggested herein. Thus, selectively orienting the modules themselves ispreferably conducted to compensate for different tape dimensions(explained in further detail below).

According to one embodiment, one or both the arrays of transducers maybe in one or more chiplets, which may be thin film structures that aresmaller than the module itself, and coupled thereto. A chiplet mayinclude at least one of: a read transducer and a write transducer, orany combination thereof. Moreover, a chiplet is preferably coupled to acarrier, the carrier providing a portion of the tape bearing surface. Indifferent embodiments, a chiplet may be coupled to the carrier using anadhesive, an electrostatically dissipative adhesive, or any othercoupling mechanism which would be apparent to one skilled in the artupon reading the present description. Moreover, one or more of thechiplets may be longitudinally positioned about orthogonal to theintended direction of tape travel, or at an angle relative thereto. Achiplet may be an independently formed chip that was created separatelyand away from the carrier, or a chip formed on the carrier but notextending the full span of the magnetic tape passing thereacross.

In a further embodiment, one or more of the modules for a given head maybe formed full span.

The arrays of transducers may be formed by known processes.

The first and/or second edges 1128, 1130 may be defined by any knownprocess, such as dicing, lapping, polishing, etc.

With continued reference to FIGS. 11A-11C, the two modules 1124, 1126,are preferably fixed relative to each other. In view of the presentdescription, “fixed” is intended to mean constrained from a directionalmovement relative to each other such that the arrays of each maintain afixed position relative to each other. According to various embodiments,the tape bearing surfaces may be fixed relative to each other by usingbrackets, fasteners, adhesives, cables, a common support structure, etc.Moreover, according to different embodiments, the tape bearing surfacesare preferably fixed relative to each other prior to being installed inthe system 1100, head, etc. depending on the desired embodiment.

The two modules 1124, 1126, are preferably fixed such that the first andsecond edges 1128, 1130 of tape bearing surface 1102, are oriented aboutparallel to the first and second edges 1128, 1130 of tape bearingsurface 1104, respectively. Therefore, the first edge 1128 for both tapebearing surfaces 1102, 1104, may be oriented about orthogonal to anintended direction 1120 of tape travel thereacross.

In a preferred embodiment, the modules are fixed such that the distancebetween the arrays of transducers in a direction parallel to theintended direction of tape travel is minimized. Reducing the spacingbetween the transducers in a direction parallel to the intendeddirection of tape travel improves the recording quality for a givensystem, e.g., by reducing noise while reading and/or writing, minimizingthe effects of tape skew thereby keeping the transducers within theirrespective data tracks, etc. Therefore, with continued reference toFIGS. 11A-1C, the distance y between the arrays 1106, 1108 oftransducers 1110 may be minimized. As shown, the second edge 1130 ofboth tape bearing surfaces 1102 and 1104 is preferably oriented aboutparallel to the longitudinal axes 1112, 1113 of the arrays 1106, 1108 oftransducers 1110. In one embodiment, the module may be formed with thesecond edge oriented about parallel to the arrays of transducers, e.g.,by using grinding, masking, lapping, etc. According to various otherembodiments, second edge may first be formed about orthogonal to thedirection of tape travel (see FIG. 12), and then cut, etched, ground,etc., about parallel to the arrays 1106, 1108 of transducers 1110. Inyet other embodiments, the distance between arrays is made larger toaccommodate writers having narrower widths.

With continued reference to FIGS. 11A-11C, the second edge 1130 of tapebearing surface 1102 and the second edge 1130 of tape bearing surface1104 are preferably positioned adjacent each other. This favorablyallows the modules 1124, 1126 to be positioned such that the arrays1106, 1108 of transducers 1110 may be closer together in a directionparallel to the intended direction of tape travel.

However, according to another embodiment, which is in no way intended tolimit the invention, the second edge 1130 for one or both the tapebearing surfaces 1102, 1104 may be oriented about parallel to the firstedge 1128 of one or both the tape bearing surfaces 1102, 1104. Asillustrated in FIG. 12, the second edges 1130 are oriented aboutparallel to the first edges 1128 of both the tape bearing surfaces 1102,1104, which are also oriented about orthogonal with the intendeddirection of tape travel.

Moreover, referring again to FIGS. 11A-11C, the modules 1124, 1126, arepreferably fixed such that the axes 1112, 1113 of the arrays 1106, 1108are oriented about parallel to each other. As shown, the axes 1112, 1113of each array of transducers are defined by the dashed lines that liebetween opposite ends thereof, e.g., the ends positioned farthest apart.However, the modules are preferably selectively orientable (e.g.,rotatable or tiltable) as a single structure about a pivot point whileremaining fixed relative to each other, as will soon become apparent.

As referred to above, the modules may be set to a nominal angle in thedrive so that the transducers of the arrays are preferably aligned alongthe data tracks 906 of a tape 902 having nominal tape conditions (seeθ_(nom) of FIG. 9A). As illustrated in FIG. 11A, the modules arepreferably oriented such that the first edge 1128 of the modules isnominally oriented about orthogonal to an intended direction 1120 oftape travel thereacross. However, in other embodiments, the first and/orsecond edge 1128, 1130 of the modules of FIG. 11A may be nominallyoriented orthogonally to an intended direction 1120 of tape travelthereacross. Moreover, the first and/or second edges 1128, 1130 of themodules may be nominally oriented at an angle relative to a directionorthogonal to the intended direction of tape, depending on the desiredembodiment.

According to different embodiments, the first and or second edges 1128,1130 may be set to a nominal orientation when a new tape is loaded, whenthe tape is stopped, when a read and/or write operation is initiated,etc. However, once the tape no longer has nominal conditions, e.g., thetape begins to run; fluctuations in tape skew, tape lateral expansion orcontraction is present, PES, etc.; etc., the modules may be selectivelyoriented from the nominal orientation, such that the transducers arepreferably kept within the data tracks of the tape for the presentconditions. This follows the reasoning presented above in relation toFIGS. 9A-9C illustrating one method of compensating for different tapecharacteristics.

In one embodiment, which is in no way intended to limit the invention,the modules may be oriented from the nominal angle to a desired angleduring read and/or write operation. Accordingly, the modules may beoriented during run time to compensate for fluctuating conditions, e.g.,tape skew, PES variations, etc. In different embodiments, the modulesmay be selectively oriented periodically; upon request; instantaneously;when a limit is reached e.g., a time limit, tape lateral contraction,tape lateral expansion, etc.; etc., depending on the desired embodiment.

Referring again to FIGS. 11A-11B, the arrays 1106, 1108 of thetransducers 1110 in the first and second modules 1124, 1126 arepreferably longitudinally oriented at an angle φ relative to the firstedge of the air bearing surfaces, as described above. As illustrated inFIG. 11B, although the angle φ between the array of transducers andfirst edge of the tape bearing surface is fixed, the modules themselvesmay be selectively oriented to an angle λ in relation to a referenceline 1122 orthogonal to the intended direction of tape travel. Moreover,the modules may rotate about a pivot point which may be located invarious locations relative to the head, depending on the desiredembodiment.

With continued reference to FIG. 11B, the modules may be selectivelyoriented such that the combined angular difference β between thereference line 1122 and the axes 1112, 1113 of the arrays 1106, 1108 oftransducers 1110 (i.e., φ+λ=β) is within a preferred range. According tovarious embodiments, the preferred range is between greater than about0.05° and about 10°, more preferably between greater than about 0.2° andabout 8°, and ideally between greater than about 0.25° and about 6°,relative to the first edge 1128 of the tape bearing surfaces 1102, 1104,respectively, to compensate for tape lateral expansion, skew, PES, etc.

Angles of orientation greater than within the specified range (e.g.,greater than about 10°) may be undesirable as the higher angles maycause steering of the tape when used. However, as described above, theangles of orientation within the specified range unexpectedly andunforeseeably have been found via experimentation to not result insteering of the tape. Moreover, it is more difficult to distinguishbetween skew and tape lateral expansion and/or contraction when anglesof orientation of the tape bearing surfaces are greater than within thespecified range. This may cause difficulties when matching thedimensional conditions of the tape and/or orientation of the tapebearing surfaces of the current operation to that of the previousoperation (explained in further detail below). It should also be notedthat the angles φ, λ illustrated in FIGS. 11A-11B are exaggerated (e.g.,larger than within the desired range), and are in no way intended tolimit the invention.

Depending on the desired embodiment, the modules themselves may also beoffset to effect the shifting of the transducer arrays, e.g., as shownby the offset (offset) in FIG. 11C. Alternatively, the transducer arraysand/or chiplets may be positioned on the respective module in aspecified position to effect the offset while the modules themselves arenot offset in the drive; or combinations thereof.

With continued reference to FIG. 11C, the system 1100 includes amechanism 1114, such as a tape dimensional instability compensationmechanism for orienting the head 1101 to control a transducer pitchpresented to a tape. In another embodiment, the tape dimensionalinstability compensation mechanism 1114 may oriented the modules tocontrol the transducer pitch presented to a tape. The tape dimensionalinstability compensation mechanism 1114 preferably allows for theorienting of the tape bearing surfaces to be done while the modules arereading and/or writing. The tape dimensional instability compensationmechanism 1114 may be any known mechanism suitable for orienting themodules. Illustrative tape dimensional instability compensationmechanisms 1114 include worm screws, voice coil actuators, thermalactuators, piezoelectric actuators, etc.

The system 1100 further includes a controller 1116. In one embodiment,the controller 1116 may be configured to control the tape dimensionalinstability compensation mechanism 1114 for orienting the modules basedon a physical and/or running state of the tape, e.g., lateral expansionand/or contraction, skew, PES, etc. According to various embodiments,the state of expansion of the tape may be based on a readback signal ofthe tape, e.g., servo signals, data signals, a combination of both, etc.In another embodiment, the dimensional conditions of the tape and/ororientation of the modules when the tape was written may be retrievede.g., from a database, cartridge memory, etc., and the orientationthereof may be set based thereon to about match the transducer pitch ofthe current operation to that of the previous operation.

In various embodiments, additional logic, computer code, commands, etc.,or combinations thereof, may be used to control the tape dimensionalinstability compensation mechanism 1114 for adjusting the orientation ofthe modules based on a skew of the tape. Moreover, any of theembodiments described and/or suggested herein may be combined withvarious functional methods, depending on the desired embodiment.

FIG. 11D depicts a variation of an apparatus as shown in FIG. 11A, andlike elements are numbered the same in both FIGS. Referring to FIG. 11D,a spacer member 1150 extends between the second edges 1130 of the tapebearing surfaces. The spacer member 1150 may be recessed from a plane ofthe tape bearing surfaces, but is preferably coplanar therewith and/orotherwise forms a portion of the overall tape bearing surface of thehead.

In one embodiment, the spacer member 1150 includes an electro-magneticshield 1152 for shielding the array of transducers from the second arrayof transducers. Such shield may be formed of any suitable material knownin the art, such as NiFe, CoFe, copper, aluminum, etc. and combinationsthereof. The shield may extend from the tape bearing surface, or somepoint therebelow, in a height direction (into the tape bearing surface),preferably for a distance that provides the desired shielding effect.For example, the shield may have a height similar to that of shields ofthe transducers.

Although two modules are illustrated in FIGS. 11A-11D, in otherembodiments, an apparatus or system may include any number of modulese.g., at least two, at least three, at least four, a plurality, etc.depending on the desired embodiment. Moreover, the modules may bepositioned with any orientation relative to other modules of the system,depending on the desired embodiment.

As alluded to above, a miniskirt design may be incorporated with any ofthe embodiments described herein, thereby allowing relative motionbetween portions of a magnetic head, in some embodiments, which togethermay provide a tape bearing surface. As previously described, this mayincrease the data read and/or write performance of various embodimentspresented herein, e.g., by improving compensation for tape skew,position error signal (PES), TDI, etc. Moreover, according to furtherembodiments, when paired with selectively tiltable arrays of datatransducers e.g., as described above with reference to the embodimentsin FIGS. 10-11D, a miniskirt design may provide even greaterimprovements to data read and/or write performance.

Referring now to FIGS. 13A-13B, the embodiments depicted thereinillustrate an apparatus 1300, in accordance with one embodiment. As anoption, the present apparatus 1300 may be implemented in conjunctionwith features from any other embodiment listed herein, such as thosedescribed with reference to the other FIGS. Of course, however, suchapparatus 1300 and others presented herein may be used in variousapplications and/or in permutations which may or may not be specificallydescribed in the illustrative embodiments listed herein. Further, theapparatus 1300 presented herein may be used in any desired environment.Thus FIGS. 13A-13B (and the other FIGS.) should be deemed to include anyand all possible permutations.

Looking to FIGS. 13A-13B, the apparatus 1300 includes a magnetic head1302 which has a first portion 1304 and a second portion 1306, e.g.,which form a miniskirt-head assembly. In a preferred embodiment, thefirst portion 1304 and a second portion 1306 together provide a tapebearing surface (TBS). However, according to further embodiments, themagnetic head 1302 may include additional lips, outriggers, portions,etc. which may add to the surface area of the TBS, e.g., to support awider range of tape sizes.

Additionally, the first portion 1304 of the magnetic head 1302 has anopening 1308 which may at least partially encircle the second portion1306. According to the illustrative embodiment depicted in FIGS. 13A-13Band 16, the opening 1308 may fully encircle the second portion 1306;however, in other embodiments, the opening 1308 of the first portion1304 may incorporate different designs and therefore may only partiallyencircle the second portion 1306, as shown in FIGS. 14-15.

With continued reference to FIGS. 13A-13B, the second portion 1306 isdepicted as including two modules 1124, 1126. It should be noted thatvarious components of FIGS. 13A-13B have common numbering with those ofFIGS. 11A-11D, thereby signifying components having similar and/or thesame designs as those described above. It follows that the modules 1124,1126 of the second portion 1306 may include any of the embodimentsdescribed above with reference to FIGS. 11A-11D, depending on thedesired embodiment. Thus, according to one embodiment, each of themodules 1124, 1126 of the second portion 1306 in FIGS. 13A-13B includean array 1106, 1108 of transducers 1110, respectively. However,according to other embodiments, the second portion 1306 may include atleast one array of transducers, as described in detail below withreference to FIGS. 14-15.

Still looking to FIGS. 13A-13B, the modules 1124, 1126 of the secondportion 1306 each have a first edge 1316, and a second edge 1318opposite the first edge 1316. As depicted, the first edge 1316 isoriented orthogonally to the intended direction 1120 of tape travelwhile the second edge 1318 is oriented about parallel to the arrays oftransducers 1106, 1108. However, according to another illustrativeembodiment, the first and second edges 1316, 1318 may both be orientedabout parallel to the arrays of transducers 1106, 1108, as described indetail below with reference to FIG. 16.

Similar to the description provided above, the second portion 1306 asillustrated in FIGS. 13A-13B, has two arrays 1106, 1108 of transducers1110. Furthermore, the arrays 1106, 1108 of transducers 1110 havelongitudinal axes 1112, 1113 respectively, which are defined betweenopposite ends thereof. The longitudinal axes 1112, 1113 of the arrays1106, 1108 are oriented about parallel to each other such that a firstof the arrays 1106 is offset from the second of the arrays 1108 in adirection parallel to the axes 1112, 1113 of the arrays. According to apreferred embodiment, the arrays may be offset enough such that at leastsome of the transducers 1110 of the first array 1106 are about alignedwith at least some of the transducers 1110 of the second array 1108 inan intended direction 1120 of tape travel thereacross. This preferablyallows for the transducers of both arrays to align with the data tracksof a tape being read and/or written to. Moreover, this configurationenables read verified writing of data, thereby desirably reducing writeerrors, data loss, etc.

Moreover, the arrays 1106, 1108 of transducers 1110 are positioned in acanted configuration, such that the longitudinal axis 1112, 1113 of eachof the arrays 1106, 1108 are oriented at an angle φ relative to a line1310 oriented orthogonally to the intended direction 1120 of tape travelthereacross. According to various embodiments, the angle φ may bebetween greater than about 0.2° and about 10°, but could be higher orlower e.g., to compensate for tape lateral expansion, skew, PES, etc.,depending on the desired embodiment. Furthermore, according to variousembodiments, the orientation of the arrays 1106, 1108 of transducers1110 and/or the orientation of the modules 1124, 1126 may include any ofthe embodiments as discussed in detail above with reference to FIGS.10-12.

According to yet another embodiment, FIG. 16 illustrates an apparatus1600 having modules 1124, 1126 positioned such that the first and secondedges 1316, 1318 of each of the modules 1124, 1126 are oriented aboutparallel to the arrays of transducers 1106, 1108. Additionally, thearrays of transducers 1106, 1108 may be oriented at an angle φ relativeto a line 1310 oriented orthogonally to the intended direction 1120 oftape travel thereacross. Thus, the first and second edges 1316, 1318 ofeach of the modules 1124, 1126 may be oriented at an angle φ relative tothe line 1310 as well. It should be noted that various components ofFIG. 16 have common numbering with those of FIGS. 13A-13B, therebysignifying components having similar and/or the same designs as thosedescribed above.

In preferred embodiments, the angle φ keeps the transducers 1110 withintheir respective data tracks on the tape 902, e.g., at least for anominal tape width. Moreover, small angular adjustments may additionallybe made to the modules themselves to compensate for changing tapeconditions as previously described. However, with continued reference tothe apparatus 1300 of FIGS. 13A-13B, the first portion 1304 and/orsecond portion 1306 may be selectively positionable depending on thedesired embodiment, e.g., to achieve the small angular adjustments tocompensate for changing tape conditions, while minimizing powerconsumption, run time, accuracy, etc., as will soon become apparent.

Looking now to the partial cross-sectional view of FIG. 13B, theapparatus 1300 has a mechanism 1312 for orienting the first and/orsecond portions 1304, 1306, e.g., to control a transducer pitchpresented to a tape. Therefore, according to different embodiments, themechanism may be able to compensate for TDI, tape skew and/or trackfollowing of only the first portion, only the second portion, or boththe first and second portions, depending on the configuration of theapparatus. Preferably, by controlling the transducer pitch presented toa tape, the mechanism 1312 may be able to compensate for TDI, and tapeskew, while adjustments may also be made to the orientation of thetransducers in a direction orthogonal to the intended direction 1120 oftape travel to allow for track following. Furthermore, the mechanism mayinclude any of the embodiments described above, e.g., see 1114 of FIG.11C.

According to one embodiment, the first and second portions 1304, 1306may be selectively positionable together for compensating for tape skewand for track following. For example, the transducer pitch presented toa tape of the first and second portions 1304, 1306, in addition to thepositioning of the first and second portions 1304, 1306 in a directionorthogonal to an intended direction of tape travel (e.g., relative todata tracks on a tape), as a single unit may be adjusted together tofollow tape skew, TDI and track following.

However, according to other embodiments, the first and second portions1304, 1306 may be selectively positionable relative to each other. Forexample, the second portion may be independently positionable relativeto the first portion, e.g., for compensating for tape skew and/or fortrack following.

In one embodiment, the first and second portions 1304, 1306 may beselectively positionable together for compensating for tape skew, whilethe second portion may also be selectively positionable in a directionorthogonal to the intended direction 1120 of tape travel, e.g., fortrack following. For example, the transducer pitch presented to a tapeof the first and second portions 1304, 1306 may be adjusted together tofollow tape skew, while the second portion 1306 track follows andcompensates TDI within the first portion 1304.

In yet another embodiment, the first portion 1304 may be fixed in theapparatus 1300 thereby preventing movement of the first portion 1304relative to the bulk of the apparatus 1300. However, the second portion1306 is selectively positionable for compensating for tape skew and fortrack following.

In a further embodiment, the first portion 1304 is coupled to a coarseactuator that may move the first and second portions along a lineoriented orthogonally to the intended direction 1120 of tape travel. Thefirst portion may not be tiltable relative to the line. However, thesecond portion 1306 may be selectively positionable for compensating fortape skew and for track following.

As alluded to above, by incorporating the ability to selectivelycompensate for TDI, tape skew and/or track following by adjustment ofonly the first portion, only the second portion, or both the first andsecond portions depending on the desired embodiment, the efficiency ofthe apparatus 1300 improves greatly. For example, if a tape is beingread and/or written to and the tape experiences skew that causes thedata tracks to become misaligned with the transducers of the apparatus,but not enough skew to cause the tape to be in danger of sliding off theedge of the overall TBS, adjustments may be made to the positioning ofthe second portion of the apparatus such that the transducers of thesecond portion may be realigned with the data tracks on the skewed tapewithout having to adjust the positioning of the entire TBS whenappropriate, e.g., both the first and the second portions of themagnetic head.

In various embodiments, the relative motion between the first and secondportions 1304, 1306, or lack thereof, as explained in the embodimentsabove may be achieved by incorporating a number of different designs.

In one embodiment, the entire assembly may be selectively positionabletogether, e.g., to compensate for TDI, tape skew, and track following.According to one embodiment, to achieve this uniform positioning, thefirst and second portions 1304, 1306 may be coupled to each other, e.g.,using adhesives, straps, fasteners, braces, etc., such that the firstand second portions are fixed relative to each other. However, inanother embodiment, the mechanism 1312 may be programmed (e.g.,controlled) by a controller to position the first and second portions1304, 1306 in the same manner. In other words, the mechanism may exert arelative amount of force on each of the first and second portions 1304,1306 in an appropriate direction e.g., to ensure that the transducerpitch presented to a tape for each of the portions 1304, 1306 is aboutthe same.

Therefore, referring again to FIG. 13B, the apparatus 1300 includes acontroller 1314 which may be of a type known in the art and/or mayinclude any of the embodiments described above (e.g., see 1116 of FIG.11C). In various embodiments, the controller 1314 may be configured tocontrol the mechanism 1312 for orienting the first and/or secondportions 1304, 1306 (e.g., having the transducers), based on a state ofexpansion of the tape, skew of the tape, PES, etc., as determined by theapparatus 1300. Therefore, the controller 1314 is preferablyelectrically coupled to the mechanism 1312 via a wire, a cable, a busconfiguration, wirelessly, etc., depending on the desired embodiment,such that information may be transferred therebetween.

Although only one mechanism 1312 is shown in FIG. 13B for positioningboth the first and second portions 1304, 1306, in other embodiments,each of the first and second portions 1304, 1306 may be coupled to theirown respective mechanisms. Furthermore, each of the mechanisms ispreferably coupled (e.g., electrically connected) to the controller 1314for operation thereof.

With continued reference to FIG. 13B, the first and second portions1304, 1306, e.g., forming the TBS, have a generally arcuate crosssectional profile. An illustrative range of the average radius ofcurvature of the first portion 1304 is between about 10 and about 60 mm.According to a preferred embodiment, the radius of the arcuate crosssectional profile of the TBS may be about 30 mm, but may be higher orlower depending on the desired embodiment.

Furthermore, although the second portion 1306 of the apparatus 1300 isillustrated as including modules 1124, 1126 each having an array 1106,1108 of transducers 1110 respectively, in other embodiments the secondportion 1306 may have only one module and/or one array of transducers,three arrays of transducers, four or more arrays of transducers, etc.

Moreover, the second portion 1306 may protrude beyond the TBS of thefirst portion 1304 towards the tape, e.g., by up to about 1 millimeter.

FIGS. 14-15 depict apparatuses 1400, 1500, according to respectiveexemplary design configurations. As an option, the present apparatuses1400, 1500 may be implemented in conjunction with features from anyother embodiment listed herein, such as those described with referenceto the other FIGS. Of course, however, such apparatuses 1400, 1500 andothers presented herein may be used in various applications and/or inpermutations which may or may not be specifically described in theillustrative embodiments listed herein. Further, the apparatuses 1400,1500 presented herein may be used in any desired environment. Thus FIGS.14-15 (and the other FIGS.) should be deemed to include any and allpossible permutations. It should also be noted that FIG. 15 illustratessimilar components as the embodiment of FIG. 14. Accordingly, variouscomponents of FIG. 15 have common numbering with those of FIG. 14, butare in no way intended to limit the invention in any way.

Referring now to FIGS. 14-15, the first portion 1404 of the magnetichead 1412 has an opening 1402 which partially encircles the secondportion 1406. According to the embodiments illustrated in FIGS. 14-15,the opening 1402 of the first portion 1404 incorporates a design havinggaps between opposing parts of the first portion 1404, thereby onlypartially encircling the second portion 1406.

Furthermore, the second portion 1406 has a first edge 1408 orientedorthogonal to the intended direction 1120 of tape travel, and a secondedge 1410 opposite the first edge 1408. However, unlike the secondportion 1306 shown in FIGS. 13A-13B for which the second edge of eachmodule 1124, 1126 of the second portion 1306 is oriented about parallelto the arrays of transducers, the second edge 1410 of the second portion1406 in FIGS. 14-15 is oriented about parallel to the first edge 1408 ofthe second portion 1406.

Looking now to the embodiment depicted in FIG. 14, the apparatus 1400includes a second portion 1406 having of a single module which includestwo arrays 1414, 1416 of transducers. Alternatively, according toanother embodiment, FIG. 15 illustrates the apparatus 1400 having asecond portion 1406 which includes a single module having one array 1502of transducers.

According to various embodiments, any of the arrays of transducersand/or second portion 1406 from either embodiment depicted in FIGS.14-15 may include any of the embodiments described and/or suggestedherein.

Referring to FIG. 15, the second portion 1406 may be movable relative tothe first portion 1404 in a direction 1502 orthogonal to the intendeddirection 1120 of tape travel.

According to an exemplary embodiment, a method for orienting moduleshaving transducers, may be implemented in accordance with oneembodiment. Such method may be implemented by the controller of FIG. 11Cand/or FIG. 13B but is not limited thereto. As an option, the presentmethod may be implemented in conjunction with features from any otherembodiment listed herein, such as those described with reference to theother FIGS. Of course, however, such method and others presented hereinmay be used in various applications and/or in permutations which may ormay not be specifically described in the illustrative embodiments listedherein. Further, the method presented herein may be used in any desiredenvironment.

According to one embodiment, the method may include determining adesired pitch for transducers for reading and/or writing to a magnetictape. Moreover, the method may optionally include determining a state ofexpansion of the tape. According to one embodiment, the state of thetape may be used to determine the desired pitch for transducers whenreading and/or writing. An exemplary mechanism for establishing theproper pitch is to use the timing interval read by two servo readers todetermine the state of the tape, e.g., contracted, expanded or nominal.Although a preferred mode is to use servo data, this is not required.Thus, it may be desirable to determine the state of the tape, e.g., byincorporating any of the embodiments described and/or suggested hereinand/or known processes, when determining the desired pitch. However,according to other embodiments, the pitch may be determined using anyembodiment described and/or suggested herein, or combinations thereof.

The method further includes orienting a head to achieve the desiredpitch, the head having a tape bearing surface having a first edge; andan array of transducers in and/or adjacent the tape bearing surface, thearray of transducers being longitudinally oriented at an angle relativeto the first edge, the angle being between greater than 0.2°and about8°. In a preferred embodiment, the first edge may be nominally orientedorthogonally to a direction of tape travel thereacross.

In another embodiment, various steps of the method may be performedconcurrently. For example, in one embodiment the proper transducer pitchmay be based on data signals. One way to implement this is by firstsetting the transducer pitch at a nominal value by selecting a nominalangle of orientation, and then adjusting the orientation thereof toobtain a better readback quality across the read channels. The qualitymay be determined for example by finding the lowest error rate, bestsignal to noise level, etc.

As an option, the system may continue or periodically monitor theappropriate signals and adjust the orientation. Adjustments can beperformed any time, such as during an initialization period prior toreading or writing user data, during readback or writing operations,etc.

It will be clear that the various features of the foregoing systemsand/or methodologies may be combined in any way, creating a plurality ofcombinations from the descriptions presented above.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as “logic,” a “circuit,” “module,” or“system.” Furthermore, aspects of the present invention may take theform of a computer program product embodied in one or more computerreadable medium(s) having computer readable program code embodiedthereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a non-transitory computer readable storage medium. A computerreadable storage medium may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thenon-transitory computer readable storage medium include the following: aportable computer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a portable compact disc read-only memory (e.g.,CD-ROM), a Blu-ray disc read-only memory (BD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a non-transitory computerreadable storage medium may be any tangible medium that is capable ofcontaining, or storing a program or application for use by or inconnection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a non-transitory computer readable storage medium and that cancommunicate, propagate, or transport a program for use by or inconnection with an instruction execution system, apparatus, or device,such as an electrical connection having one or more wires, an opticalfibre, etc.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fibre cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer, for example through the Internet using an Internet ServiceProvider (ISP).

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart(s) and/orblock diagram block or blocks.

It will be further appreciated that embodiments of the present inventionmay be provided in the form of a service deployed on behalf of acustomer.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

What is claimed is:
 1. An apparatus, comprising: a magnetic head, themagnetic head having: a first portion and a second portion, the firstportion and the second portion together providing a tape bearingsurface, wherein the first portion has two pieces flanking the secondportion in an intended direction of tape travel thereacross, the secondportion having at least one array of transducers, wherein a longitudinalaxis of each of the at least one array is defined between opposite endsthereof, wherein the longitudinal axis of each of the at least one arrayof transducers is oriented at an angle relative to the line orientedorthogonally to an intended direction of tape travel, the angle beingbetween 0.2° and about 10°.
 2. An apparatus as recited in claim 1,wherein the tape bearing surface has a generally arcuate cross sectionalprofile.
 3. An apparatus as recited in claim 1, wherein the secondportion has a first edge oriented orthogonally to the intended directionof tape travel thereacross, and a second edge opposite the first edge,the second edge being oriented about parallel to the first edge.
 4. Anapparatus as recited in claim 1, comprising: a mechanism for orientingthe second portion to control a transducer pitch presented to a tape. 5.An apparatus as recited in claim 4, wherein the first and secondportions are selectively positionable for compensating for tape skew,wherein the second portion is selectively positionable in a directionorthogonal to the intended direction of tape travel for track following.6. An apparatus as recited in claim 4, wherein the first and secondportions are selectively positionable for compensating for tape skew andfor track following.
 7. An apparatus as recited in claim 6, wherein thesecond portion is independently positionable relative to the firstportion.
 8. An apparatus as recited in claim 4, wherein the firstportion is fixed in the apparatus thereby preventing movement thereofrelative to the apparatus, wherein the second portion is selectivelypositionable for compensating for tape skew and for track following. 9.An apparatus as recited in claim 4, wherein the first portion is coupledto a coarse actuator, wherein the first portion is not tiltable relativeto the line oriented orthogonally to the intended direction of tapetravel, wherein the second portion is selectively positionable forcompensating for tape skew and for track following.
 10. An apparatus asrecited in claim 4, comprising a controller configured to control themechanism for orienting the at least one array of transducers based on astate of expansion of the tape determined by the apparatus.
 11. Anapparatus as recited in claim 4, comprising a controller configured tocontrol the mechanism for orienting the at least one array oftransducers based on skew of the tape.
 12. An apparatus as recited inclaim 1, wherein the first portion and the second portion are fixedrelative to each other.
 13. An apparatus as recited in claim 1, whereinthe second portion is selectively positionable relative to the firstportion.
 14. An apparatus as recited in claim 1, comprising: a drivemechanism for passing a magnetic medium over the magnetic head; and acontroller electrically coupled to the magnetic head.